docs: def _has_streamhandler(logger, level=None, fmt=LOG_FORMAT,
                         stream=DEFAULT_STREAM):
      """Check the named logger for an appropriate existing StreamHandler.
  
      This only returns True if a StreamHandler that exaclty matches
      our specification is found. If other StreamHandlers are seen,
      we assume they were added for a different purpose.
      """
      # Ensure we are talking the same type of logging levels
      # if they passed in a string we need to convert it to a number
      if isinstance(level, basestring):
          level = logging.getLevelName(level)
  
      for handler in logger.handlers:
          if not isinstance(handler, logging.StreamHandler):
              continue
          if handler.stream is not stream:
              continue
          if handler.level != level:
              continue
          if not handler.formatter or handler.formatter._fmt != fmt:
              continue
          return True
      return False